U.S. patent application number 10/678645 was filed with the patent office on 2004-07-22 for utilization of substituted imidazo[1,2-a]-pyridine compounds in pharmaceutical formulations.
Invention is credited to Hennies, Hagen-Heinrich, Sundermann, Bernd, Sundermann, Corinna.
Application Number | 20040142961 10/678645 |
Document ID | / |
Family ID | 7680630 |
Filed Date | 2004-07-22 |
United States Patent
Application |
20040142961 |
Kind Code |
A1 |
Sundermann, Corinna ; et
al. |
July 22, 2004 |
Utilization of substituted imidazo[1,2-a]-pyridine compounds in
pharmaceutical formulations
Abstract
Methods of using pharmaceutical formulations with
imidazo[1,2-a]-pyridine compounds as active ingredients to inhibit
nitric oxide synthase are disclosed. Treatments of certain
conditions using imidazo[1,2-a]-pyridine compounds are also
disclosed.
Inventors: |
Sundermann, Corinna;
(Aachen, DE) ; Hennies, Hagen-Heinrich;
(Simmerath, DE) ; Sundermann, Bernd; (Aachen,
DE) |
Correspondence
Address: |
CROWELL & MORING LLP
INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Family ID: |
7680630 |
Appl. No.: |
10/678645 |
Filed: |
October 3, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10678645 |
Oct 3, 2003 |
|
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PCT/EP02/03795 |
Apr 5, 2002 |
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Current U.S.
Class: |
514/303 |
Current CPC
Class: |
A61P 25/00 20180101;
A61P 25/04 20180101; A61P 17/02 20180101; A61P 25/16 20180101; A61P
9/10 20180101; A61P 43/00 20180101; A61P 25/06 20180101; A61P 29/00
20180101; A61P 7/12 20180101; A61P 25/28 20180101; A61P 31/04
20180101; A61P 25/14 20180101; A61K 31/437 20130101; A61P 3/10
20180101; A61P 19/00 20180101 |
Class at
Publication: |
514/303 |
International
Class: |
A61K 031/4745 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 2001 |
DE |
101 17 183.8 |
Claims
What is claimed is:
1. A method of inhibiting nitric oxide synthase in a mammal, said
method comprising administering to said mammal an effective nitric
oxide synthase inhibiting amount of at least one
imidazo[1,2-a]-pyridine compound corresponding to formula I
6wherein, R.sup.1 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, an unsubstituted or at
least monosubstituted aryl or heteroaryl radical, H, F, Cl, Br, I,
CN, NO.sub.2, NH.sub.2, C(.dbd.O)R.sup.5, CO.sub.2H,
CO.sub.2R.sup.6, OH or OR.sub.7; R.sup.2 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl radical,
an unsubstituted or at least monosubstituted C.sub.2-8-alkenyl
radical, an unsubstituted or at least monosubstituted
C.sub.2-8-alkinyl radical, a C.sub.3-8-cycloalkyl radical, a
C.sub.3-8cycloalkyl radical which is bonded via a
C.sub.1-8-alkylene group, an unsubstituted or at least
monosubstituted aryl or heteroaryl radical, H, F, Cl, Br, I, CN,
NO.sub.2, NH.sub.2, C(.dbd.O)R.sup.5, CO.sub.2H, CO.sub.2R.sup.6 or
OH; R.sup.3 represents an unsubstituted or at least monosubstituted
C.sub.1-8-alkyl radical, an unsubstituted or at least
monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, an unsubstituted or at
least monosubstituted aryl or heteroaryl radical, an unsubstituted
or at least monosubstituted aryl or heteroaryl radical which is
bonded via a C.sub.1-8-alkylene group, CH.sub.2SR.sup.8,
CH.sub.2OR.sup.8 or H; R.sup.4 represents H, an unsubstituted or at
least monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or
at least monosubstituted C.sub.2-8-alkenyl radical, an
unsubstituted or at least monosubstituted C.sub.2-8-alkinyl
radical, an unsubstituted or at least monosubstituted aryl or
heteroaryl radical, or an unsubstituted or at least monosubstituted
aryl or heteroaryl radical which is bonded via a C.sub.1-8-alkylene
group; R.sup.5 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, a C.sub.3-7-heterocyclyl
radical, an unsubstituted or at least monosubstituted aryl or
heteroaryl radical or an unsubstituted or at least monosubstituted
aryl or heteroaryl radical which is bonded via a C.sub.1-8-alkylene
group; R.sup.6 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, an unsubstituted or at
least monosubstituted aryl or heteroaryl radical or an
unsubstituted or at least monosubstituted aryl or heteroaryl
radical which is bonded via a C.sub.1-8-alkylene group; R.sup.7
represents an unsubstituted or at least monosubstituted
C.sub.1-8-alkyl radical, an unsubstituted or at least
monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, an unsubstituted or at
least monosubstituted aryl or heteroaryl radical or an
unsubstituted or at least monosubstituted aryl or heteroaryl
radical which is bonded via a C.sub.1-8-alkylene group; and R.sup.8
represents an unsubstituted or at least monosubstituted
C.sub.1-8-alkyl radical, an unsubstituted or at least
monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkinyl radical, an unsubstituted
or at least monosubstituted aryl or heteroaryl radical, an
unsubstituted or at least monosubstituted aryl or heteroaryl
radical which is bonded via a C.sub.1-8-alkylene group or a
C.sub.3-8-cycloalkyl radical, or a salt thereof with a
physiologically acceptable acid.
2. A method according to claim 1, wherein said compound is present
in the form of a free base.
3. A method according to claim 1, wherein R.sup.1 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl radical,
F, Cl, Br, CN, NO.sub.2, NH.sub.2, C(.dbd.O)R.sup.5, CO.sub.2H,
CO.sub.2R.sup.6, OH or OR.sup.7.
4. A method according to claim 1, wherein R.sup.1 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl
radical.
5. A method according to claim 1, wherein R.sup.2 represents H.
6. A method according to claim 1, wherein R.sup.2 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl
radical.
7. A method according to claim 1, wherein R.sup.3 represents H.
8. A method according to claim 1, wherein R.sup.3 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl
radical.
9. A method according to claim 1, wherein R.sup.4 represents H, an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl radical,
an unsubstituted or at least monosubstituted aryl or heteroaryl
radical or an unsubstituted or at least monosubstituted aryl or
heteroaryl radical which is bonded via a C.sub.1-8-alkylene
group.
10. A method according to claim 1, wherein R.sup.5 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl radical
or an unsubstituted or at least monosubstituted aryl or heteroaryl
radical.
11. A method according to claim 1, wherein R.sup.6 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl radical
or an unsubstituted or at least monosubstituted aryl radical.
12. A method according to claim 1, wherein R.sup.7 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl radical
or an unsubstituted or at least monosubstituted aryl radical.
13. A method according to claim 1, wherein R.sup.8 represents an
unsubstituted or at least monosubstituted C.sub.1-8-alkyl radical
or an unsubstituted or at least monosubstituted aryl or heteroaryl
radical.
14. A method according to claim 1, wherein said at least one
imidazo[1,2-a]-pyridine compound is selected from the group
consisting of 2-(4-methoxy-phenyl)-7-methyl-imidazo[1,2-a]pyridine,
2,7-dimethyl-imidazo[1,2-a]pyridine,
7-methyl-imidazo[1,2-a]pyridine,
2-tert-butyl-7-methyl-imidazo[1,2-a]pyridine, and salts of any of
the foregoing with a physiologically acceptable acid.
15. A method according to claim 14, wherein said at least one
imidazo[1,2-a]-pyridine compound is present in the form of a free
base.
16. A method of treating a condition selected from the group
consisting of migraine, septic shock, multiple sclerosis,
Alzheimer's disease, inflammatory pain, diabetes, meningitis, or a
wound in a mammal, said method comprising administering to said
mammal an effective amount of a compound according to claim 1.
17. A method according to claim 16, wherein said condition is
migraine.
18. A method according to claim 16, wherein said condition is
septic shock.
19. A method according to claim 16, wherein said condition is
multiple sclerosis.
20. A method according to claim 16, wherein said condition is
Alzheimer's disease.
21. A method according to claim 16, wherein said condition is
inflammatory pain.
22. A method according to claim 16, wherein said condition is
diabetes.
23. A method according to claim 16, wherein said condition is
meningitis.
24. A method according to claim 16, wherein said condition is a
wound.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Patent
Application No. PCT/EP02/03795, filed Apr. 5, 2002, designating the
United States of America, and published in German as WO 02/080914,
the entire disclosure of which is incorporated herein by reference.
Priority is claimed based on Federal Republic of Germany Patent
Application No. DE 101 17 183.8, filed Apr. 5, 2001.
FIELD OF THE INVENTION
[0002] The present invention relates to the use of substituted
imidazo[1,2-a]-pyridine compounds and their physiologically
acceptable salts as inhibitors for nitric oxide synthase and for
the preparation of pharmaceutical formulations.
BACKGROUND OF THE INVENTION
[0003] Nitric oxide (NO) regulates numerous physiological
processes, inter alia neurotransmission, relaxation and
proliferation of the smooth musculature, adhesion and aggregation
of thrombocytes and tissue injury and inflammation. Because of the
large number of signal functions, a connection is made between
nitric oxide and a number of diseases, for example in L. J.
Ignarro, Angew. Chem. (1999), 111, pages 2002-2013 and in F. Murad,
Angew. Chem. Int. Ed. (1999), 111, pages 1976-1989. The enzyme
responsible for the physiological formation of nitric oxide, nitric
oxide synthase (NO synthase), plays an important role here in
therapeutic influencing of these diseases. Three different isoforms
of NO synthase have so far been identified, that is to say the two
constitutive forms nNO synthase and eNO synthase and the inducible
form iNO synthase (A. J. Hobbs, A. Higgs, S. Moncada, Annu. Rev.
Pharmacol. Toxicol. (1999), 39, pages 191-220; I. C. Green, P.-E.
Chabrier, DDT (1999), 4, pages 47-49; P.-E. Chabrier et al., Cell.
Mol. Life Sci. (1999), 55, pages 1029-1035).
[0004] The inhibition of NO synthase opens up new therapeutic
procedures for various diseases associated with nitric oxide (A. J.
Hobbs et al., Annu. Rev. Pharmacol. Toxicol. (1999), 39, pages
191-220; I. C. Green, P.-E. Chabrier, DDT (1999), 4, pages 47-49;
P.-E. Chabrier et al., Cell. Mol. Life Sci. (1999), 55, pages
1029-1035), such as, for example, migraine (L. L. Thomsen, J.
Olesen, Clinical Neuroscience (1998), 5, pages 28-33; L. H. Lassen
et al., The Lancet (1997), 349, 401-402), septic shock,
neurodegenerative diseases, such as multiple sclerosis, Parkinson's
disease, Alzheimer's disease or Huntington's disease,
inflammations, inflammatory pain, cerebral ischaemia, diabetes,
meningitis and arteriosclerosis. The inhibition of NO synthase can
moreover have an effect on wound healing, on tumors and on
angiogenesis and cause a non-specific immunity to microorganisms
(A. J. Hobbs et al., Annu. Rev. Pharmacol. Toxicol. (1999), 39,
pages 191-220).
[0005] Active compounds known to date which inhibit NO synthase
include, in addition to L-NMMA and L-NAME--i.e. analogues of
L-arginine, from which nitric oxide and citrulline are formed in
vivo with the participation of NO synthase--inter alia
S-methyl-L-citrulline, aminoguanidine, S-methylisourea,
7-nitroindazole and 2-mercaptoethylguanidine (A. J. Hobbs et al.,
Annu. Rev. Pharmacol. Toxicol. (1999), 39, pages 191-220).
SUMMARY OF THE INVENTION
[0006] An object of the present invention is to provide
pharmaceutical formulations which act as an inhibitor on nitric
oxide synthase.
[0007] Another object is to provide pharmaceutical formulations and
methods suitable for treatment of migraine, septic shock,
neurodegenerative diseases, such as multiple sclerosis, Parkinson's
disease, Alzheimer's disease or Huntington's disease,
inflammations, inflammatory pain, cerebral ischaemia, diabetes,
meningitis, arteriosclerosis or for wound healing.
[0008] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
[0009] Surprisingly, it has now been found that substituted
imidazo[1,2-a]-pyridine compounds corresponding to the following
formula I act as inhibitors on nitric oxide synthase and are
suitable in particular for treatment of migraine, septic shock,
neurodegenerative diseases, such as multiple sclerosis, Parkinson's
disease, Alzheimer's disease or Huntington's disease,
inflammations, inflammatory pain, cerebral ischaemia, diabetes,
meningitis, arteriosclerosis or for wound healing.
[0010] In one embodiment, the invention provides a method of
inhibiting nitric oxide synthase in a mammal. The method comprises
administering to the mammal an effective nitric oxide synthase
inhibiting amount of at least one imidazo[1,2-a]-pyridine compound
corresponding to formula I 1
[0011] wherein,
[0012] R.sup.1 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, an unsubstituted or at
least monosubstituted aryl or heteroaryl radical, H, F, Cl, Br, I,
CN, NO.sub.2, NH.sub.2, C(.dbd.O)R.sup.5, CO.sub.2H,
CO.sub.2R.sup.6, OH or OR.sup.7, preferably an unsubstituted or at
least monosubstituted C.sub.1-8-alkyl radical, F, Cl, Br, CN,
NO.sub.2, NH.sub.2, C(.dbd.O)R.sup.5, CO.sub.2H, CO.sub.2R.sup.6,
OH or OR.sup.7, particularly preferably an unsubstituted or at
least monosubstituted C.sub.1-8-alkyl radical,
[0013] R.sup.2 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, an unsubstituted or at
least monosubstituted aryl or heteroaryl radical, H, F, Cl, Br, I,
CN, NO.sub.2, NH.sub.2, C(.dbd.O)R.sup.5, CO.sub.2H,
CO.sub.2R.sup.6 or OH, preferably an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical or H, particularly
preferably H,
[0014] R.sup.3 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl, an unsubstituted or at
least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, an unsubstituted or at
least monosubstituted aryl or heteroaryl radical, an unsubstituted
or at least monosubstituted aryl or heteroaryl radical which is
bonded via a C.sub.1-8-alkylene group, CH.sub.2SR.sup.8,
CH.sub.2OR.sup.8 or H, preferably an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical or H, particularly
preferably H,
[0015] R.sup.4 represents H, an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-7-heterocyclyl radical, an
unsubstituted or at least monosubstituted aryl or heteroaryl
radical, a C.sub.3-8-cycloalkyl radical which is bonded via a
C.sub.1-8-alkylene group, a C.sub.3-7-heterocyclyl radical which is
bonded via a C.sub.1-8-alkylene group, an unsubstituted or at least
monosubstituted aryl or heteroaryl radical which is bonded via a
C.sub.1-8-alkylene group, preferably H, an unsubstituted or at
least monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or
at least monosubstituted aryl or heteroaryl radical or an
unsubstituted or at least monosubstituted aryl or heteroaryl
radical which is bonded via a C.sub.1-8-alkylene group,
[0016] R.sup.5 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-8-alkylene group, a C.sub.3-7-heterocyclyl
radical, an unsubstituted or at least monosubstituted aryl or
heteroaryl radical or an unsubstituted or at least monosubstituted
aryl or heteroaryl radical which is bonded via a C.sub.1-8-alkylene
group, preferably an unsubstituted or at least monosubstituted
C.sub.1-8-alkyl radical or an unsubstituted or at least
monosubstituted aryl or heteroaryl radical,
[0017] R.sup.6 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-4-alkylene group, an unsubstituted or at
least monosubstituted aryl radical or an unsubstituted or at least
monosubstituted aryl radical which is bonded via a
C.sub.1-8-alkylene group, preferably an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical or an unsubstituted or at
least monosubstituted aryl radical,
[0018] R.sup.7 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.3-8-cycloalkyl radical which
is bonded via a C.sub.1-4-alkylene group, an unsubstituted or at
least monosubstituted aryl radical or an unsubstituted or at least
monosubstituted aryl radical which is bonded via a
C.sub.1-8-alkylene group, preferably an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical or an unsubstituted or at
least monosubstituted aryl radical,
[0019] R.sup.8 represents an unsubstituted or at least
monosubstituted C.sub.1-8-alkyl radical, an unsubstituted or at
least monosubstituted C.sub.2-8-alkenyl radical, an unsubstituted
or at least monosubstituted C.sub.2-8-alkinyl radical, an
unsubstituted or at least monosubstituted aryl or heteroaryl
radical, an unsubstituted or at least monosubstituted aryl or
heteroaryl radical which is bonded via a C.sub.1-8-alkylene group
or a C.sub.3-8-cycloalkyl radical, preferably an unsubstituted or
at least monosubstituted C.sub.1-8-alkyl radical or an
unsubstituted or at least monosubstituted aryl or heteroaryl
radical.
[0020] Preferably, said compound is in the form of its base or a
physiologically acceptable salt.
[0021] Preferred C.sub.1-8-alkyl radicals are selected from the
group consisting of methyl, ethyl, n-propyl, 2-propyl, n-butyl,
iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, neo-pentyl,
n-hexyl, 2-hexyl and n-octyl.
[0022] Preferred C.sub.2-8-alkenyl radicals are selected from the
group consisting of ethenyl (vinyl), propenyl
(--CH.sub.2CH.dbd.CH.sub.2, --CH.dbd.CH--CH.sub.3,
--C(.dbd.CH.sub.2)--CH.sub.3), butenyl, pentenyl, hexenyl and
octenyl.
[0023] Preferred C.sub.2-8-alkinyl radicals are selected from the
group consisting of ethinyl, propinyl (--CH--C.ident.CH,
--C.ident.C--CH.sub.3), butinyl, pentinyl, hexinyl and octinyl.
[0024] If the C.sub.1-8-alkyl radical, the C.sub.2-8-alkenyl
radical or the C.sub.2-8-alkinyl radical is present in a mono- or
polysubstituted form, one or more hydrogen radical(s) is (are)
preferably replaced by a substituent selected from the group
consisting of F, Cl, Br, I, CN, NH.sub.2, NH-alkyl, NH-aryl,
NH-heteroaryl, NH-alkyl-aryl, NH-alkyl-heteroaryl, NH-heterocyclyl,
NH-alkyl-OH, N(alkyl).sub.2, N(alkyl-aryl).sub.2,
N(alkyl-heteroaryl).sub.2, N(heterocyclyl).sub.2,
N(alkyl-OH).sub.2, NO, NO.sub.2, SH, S-alkyl, S-aryl, S-heteroaryl,
S-alkyl-aryl, S-alkyl-heteroaryl, S-heterocyclyl, S-alkyl-OH,
S-alkyl-SH, OH, O-alkyl, O-aryl, O-heteroaryl, O-alkyl-aryl,
O-alkyl-heteroaryl, O-heterocyclyl, O-alkyl-OH, CHO,
C(.dbd.O)C.sub.1-6-alkyl, C(.dbd.S)C.sub.1-6-alkyl, C(.dbd.O)aryl,
C(.dbd.S)aryl, C(.dbd.O)C.sub.1-6-alkyl-aryl, 2
[0025] where n=1, 2 or 3, C(.dbd.S)C.sub.1-6-alkyl-aryl,
C(.dbd.O)-heteroaryl, C(.dbd.S)-heteroaryl, C(.dbd.O)-heterocyclyl,
C(.dbd.S)-heterocyclyl, CO.sub.2H, CO.sub.2-alkyl,
CO.sub.2-alkyl-aryl, C(.dbd.O)NH.sub.2, C(.dbd.O)NH-alkyl,
C(.dbd.O)NH-aryl, C(.dbd.O)NH-heterocyclyl,
C(.dbd.O)N(alkyl).sub.2, C(.dbd.O)N(alkyl-aryl).sub.2,
C(.dbd.O)N(alkyl-heteroaryl).sub.2, C(.dbd.O)N(heterocyclyl).sub.2,
SO-alkyl, SO.sub.2-alkyl, SO.sub.2NH.sub.2, SO.sub.3H, cycloalkyl,
aryl, heteroaryl and heterocyclyl, wherein polysubstituted
C.sub.1-8-alkyl radicals are to be understood as meaning those
radicals which are poly-, e.g. di- or trisubstituted either on
different atoms or on the same atom of the C.sub.1-8-alkyl,
C.sub.2-8-alkenyl or C.sub.2-8-alkinyl radical, for example
trisubstituted on the same carbon atom, as in CF.sub.3 or
--CH.sub.2CF.sub.3, or on different atoms, as in
--CH(OH)--CH.dbd.CH--CHC- l.sub.2. The polysubstitution can be by
identical or by different substituents. If the substituent itself
contains an alkyl group, this is preferably selected from the group
consisting of methyl, ethyl, CH.sub.2--OH and CF.sub.3.
[0026] The expression "C.sub.3-8-cycloalkyl radical" for the
purposes of the present invention includes cyclic hydrocarbons
having 3 to 8 carbon atoms, which can be saturated or unsaturated,
unsubstituted or at least monosubstituted, wherein bonding of the
cycloalkyl radical to the base skeleton of formula I can be via any
desired ring member of the cycloalkyl radical. The
C.sub.3-8-cycloalkyl radical is preferably selected from the group
consisting of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,
cycloheptyl, cyclooctyl, cyclopentenyl, cyclohexenyl, cycloheptenyl
and cyclooctenyl. The C.sub.3-8-cycloalkyl radical is particularly
preferably a cyclohexyl radical.
[0027] The expression "C.sub.3-7-heterocyclyl radical" in the
context of the present invention includes a 3-, 4-, 5-, 6- or
7-membered cyclic organic radical which contains at least 1,
optionally also 2, 3, 4 or 5 heteroatoms in the ring system,
wherein the heteroatoms can be identical or different and the
cyclic radical is saturated or unsaturated but not aromatic and can
be unsubstituted or at least monosubstituted. Bonding of the
heterocyclyl radical to the base skeleton of formula I can be via
any desired ring member of the heterocyclyl radical. The
heterocyclyl radical can also be part of a bi- or polycyclic
system. Preferred heteroatoms are selected from the group
consisting of nitrogen, oxygen and sulfur. The
C.sub.3-7-heterocyclyl radical is preferably selected from the
group consisting of tetrahydrofuryl, tetrahydropyranyl,
pyrrolidinyl, piperidinyl, piperazinyl and morpholinyl.
[0028] The expression "aryl radical" in the context of the present
invention denotes aromatic hydrocarbons, which can also be fused
with further saturated, at least partly unsaturated or aromatic
ring systems, wherein bonding of the aryl radical to the base
skeleton of formula I can be via any desired ring member of the
aryl radical. If the aryl radical contains more than one
substituent, these can be identical or different and can be present
in any desired and possible position of the aryl radical. The aryl
radical is preferably selected from the group consisting of
unsubstituted or at least monosubstituted phenyl, anthracenyl,
1-naphthyl and 2-naphthyl. The aryl radical is particularly
preferably selected from the group consisting of phenyl,
3-hydroxyphenyl, 3-methoxyphenyl, 2,3-dihydroxyphenyl,
2,3-dimethoxyphenyl and 1-naphthyl.
[0029] The expression "heteroaryl radical" in the context of the
present invention represents a 5-, 6- or 7-membered cyclic aromatic
radical which contains at least 1, optionally also 2, 3, 4 or 5
heteroatoms, wherein the heteroatoms can be identical or different
and wherein bonding to the base skeleton of formula I can be via
any desired and possible ring member of the heteroaryl radical. If
the heteroaryl radical contains more than one substituent, these
heteroaryl substituents can be identical or different and can be
present in any desired and possible position on the heteroaryl
radical. The heterocyclic radical can also be fused with further
saturated, at least partly unsaturated or aromatic ring systems.
Preferred heteroatoms are selected from the group consisting of
nitrogen, oxygen and sulfur. The heteroaryl radical is preferably
selected from the group consisting of unsubstituted or at least
monosubstituted pyrrolyl, furyl, thienyl, pyrazolyl, imidazolyl,
pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyranyl, indolyl,
indazolyl, purinyl, pyrimidinyl, indolizinyl, quinolinyl,
isoquinolinyl, quinazolinyl, carbazolyl, phenazinyl and
phenothiazinyl. Particularly preferred heteroaryl radicals are
selected from the group consisting of pyridin-2-yl, pyridin-3-yl,
furan-2-yl, furan-3-yl, 5-hydroxymethylene-furan-2-yl,
5-nitro-furan-2-yl, 5-[1,3]-dioxolane-furan-2-yl, 5-carboxylic
acid-furan-2-yl, thien-2-yl (2-thiophene), thien-3-yl (3-thiophene)
and 5-carboxylic acid-2-thiophene (5-carboxylic
acid-thien-2-yl).
[0030] If the C.sub.3-8-cycloalkyl, the C.sub.3-7-heterocyclyl, the
aryl or the heteroaryl radical is mono- or polysubstituted, this is
to be understood as meaning mono- or poly-, e.g. di-, tri- or
tetrasubstitution of one or more hydrogen atoms of the ring system
by a substituent selected from the group consisting of F, Cl, Br,
I, CN, NH.sub.2, NH-alkyl, NH-aryl, NH-heteroaryl, NH-alkyl-aryl,
NH-alkyl-heteroaryl, NH-heterocyclyl, NH-alkyl-OH, N(alkyl).sub.2,
N(alkyl-aryl).sub.2, N(alkyl-heteroaryl).sub.2,
N(heterocyclyl).sub.2, N(alkyl-OH).sub.2, NO, NO.sub.2, SH,
S-alkyl, S-cycloalkyl, S-aryl, S-heteroaryl, S-alkyl-aryl,
S-alkyl-heteroaryl, S-heterocyclyl, S-alkyl-OH, S-alkyl-SH, OH,
O-alkyl, O-cycloalkyl, O-aryl, O-heteroaryl, O-alkyl-aryl,
O-alkyl-heteroaryl, O-heterocyclyl, O-alkyl-OH, CHO,
C(.dbd.O)C.sub.1-6-alkyl, C(.dbd.S)C.sub.1-6-alkyl, C(.dbd.O)aryl,
C(.dbd.S)aryl, C(.dbd.O)C.sub.1-6-alkyl-aryl 3
[0031] where n=1, 2 or 3, C(.dbd.S)C.sub.1-6-alkyl-aryl,
C(.dbd.O)-heteroaryl, C(.dbd.S)-heteroaryl, C(.dbd.O)-heterocyclyl,
C(.dbd.S)-heterocyclyl, CO.sub.2H, CO.sub.2-alkyl,
CO.sub.2-alkyl-aryl, C(.dbd.O)NH.sub.2, C(.dbd.O)NH-alkyl,
C(.dbd.O)NH-aryl, C(.dbd.O)NH-heterocyclyl,
C(.dbd.O)N(alkyl).sub.2, C(.dbd.O)N(alkyl-aryl).sub.2,
C(.dbd.O)N(alkyl-heteroaryl).sub.2, C(.dbd.O)N(heterocyclyl).sub.2,
S(O)-alkyl, S(O)-aryl, SO.sub.2-alkyl, SO.sub.2-aryl,
SO.sub.2NH.sub.2, SO.sub.3H, CF.sub.3, .dbd.O, .dbd.S; alkyl,
cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein a
substituent can in turn be optionally substituted. The
polysubstitution may be by identical or different substituents. For
"aryl radicals", particularly preferred substituents are selected
from the group consisting of F, CF.sub.3, OH and O--CH.sub.3. For
"heteroaryl radicals", particularly preferred substituents are
selected from the group consisting of OH, O--CH.sub.3, CH.sub.2OH,
NO.sub.2, CO.sub.2H, CO.sub.2ethyl and [1,3]-dioxolane. For
"cycloalkyl radicals", particularly preferred substituents include
CO.sub.2H or CO.sub.2ethyl.
[0032] The use of at least one compound selected from the group
consisting of
[0033] 2-(4-methoxy-phenyl)-7-methyl-imidazo[1,2-a]pyridine,
[0034] 2,7-dimethyl-imidazo[1,2-a]pyridine,
[0035] 7-methyl-imidazo[1,2-a]pyridine and
[0036] 2-tert-butyl-7-methyl-imidazo[1,2-a]pyridine,
[0037] in the form of a base or a physiologically acceptable salt,
preferably in the form of the hydrochloride, as an inhibitor of
nitric oxide synthase is very particularly preferred.
[0038] If the substituted imidazo[1,2-a]-pyridine compounds of
formula I employed according to the invention or physiologically
acceptable salts thereof contain at least one asymmetric center,
they can exist in the form of their racemates, their pure
enantiomers, their pure diastereomers or in the form of a mixture
of at least two of the abovementioned stereoisomers. The
substituted imidazo[1,2-a]-pyridine compounds of formula I can also
exist in the form of a mixture of their enantiomers or
diastereomers. These mixtures may contain two or more of the
particular stereoisomers in any desired mixing ratio. Chiral
substituted imidazo[1,2-a]-pyridine compounds of formula I in
enantiomerically pure form are preferably used.
[0039] The substituted imidazo[1,2-a]-pyridine compounds of formula
I can be prepared by conventional methods known to persons skilled
in the art.
[0040] The preparation of the compounds of formula I employed
according to the invention is preferably carried out by reaction of
a substituted 2-aminopyridine corresponding to formula II, wherein
R.sup.1 and R.sup.2 have the meanings given above for formula I,
4
[0041] preferably in solution, with an .alpha.-halogenocarbonyl
compound corresponding to formula III 5
[0042] wherein the radicals R.sup.3 and R.sup.4 have the meanings
given above formula I, and X represents halogen, preferably Cl, Br
or I, water and hydrogen halide being split off.
[0043] The process for the preparation of the compounds of formula
I according to the invention is advantageously carried out under
conditions under which water and/or hydrogen halide are preferably
removed continuously from the reaction mixture.
[0044] Hydrogen halide can preferably be scavenged by addition of
soluble or insoluble organic or inorganic bases and removed from
the reaction mixture in this way.
[0045] Water can preferably be removed from the reaction mixture by
azeotropic distillation or by addition of drying agents or
hygroscopic substances.
[0046] The preparation of the compounds of formula I according to
the invention, by the above process, at temperatures of more than
100.degree. C., with or without a solvent, represents a further
possibility for removing water from the reaction mixture.
[0047] The preparation of the compounds of formula I according to
the invention, by reaction of substituted 2-aminopyridines of
formula II with .alpha.-halogenocarbonyl compounds of formula III,
wherein X represents Br, in boiling anhydrous ethanol is
particularly preferred.
[0048] The preparation of the compounds of formula I according to
the invention, by reaction of substituted 2-aminopyridines of
formula II with .alpha.-halogenocarbonyl compounds of formula III,
wherein X represents Br or Cl, in boiling anhydrous methylene
chloride or chloroform using a water separator is also
preferred.
[0049] The substituted 2-aminopyridines of formula II and the
.alpha.-halogenocarbonyl compounds of formula III are generally
commercially available or can be prepared by conventional methods
known to persons skilled in the art.
[0050] The substituted imidazo[1,2-a]-pyridine compounds of formula
I employed according to the invention can be isolated either as a
free base or as a salt after the process employed for their
preparation. The free base of the particular compound of formula I
is usually obtained after the reaction has been carried out
following the process according to the invention described above
and optionally subsequent working up by conventional methods known
to persons skilled in the art. The free base, obtained in this way
or formed in situ without isolation, of the particular compound of
formula I can then be converted into the corresponding
physiologically acceptable salt, for example by reaction with an
inorganic or organic acid, preferably with hydrochloric acid,
hydrobromic acid, sulfuric acid, phosphoric acid, methanesulfonic
acid, p-toluenesulfonic acid, carbonic acid, formic acid, acetic
acid, oxalic acid, succinic acid, tartaric acid, mandelic acid,
fumaric acid, lactic acid, citric acid, glutamic acid or aspartic
acid.
[0051] Conversion of a particular compound of formula I into the
corresponding hydrochloride can preferably also be achieved by
adding trimethylsilyl chloride (TMSCl) to the compound of formula
I, as the free base, dissolved in a suitable organic solvent, such
as, e.g. butan-2-one (methyl ethyl ketone).
[0052] If the substituted imidazo[1,2-a]-pyridine compound of
formula I according to the invention is obtained in the form of a
racemate or other mixture of its various enantiomers and/or
diastereomers by the preparation process according to the
invention, these can be separated and optionally isolated by
conventional processes known to persons skilled in the art.
Examples of such processes include chromatographic separation
processes, in particular liquid chromatography processes under
normal pressure or under elevated pressure, preferably MPLC and
HPLC processes, and processes of fractional crystallization. In
this procedure, in particular, individual enantiomers, e.g.
diastereomeric salts can be separated from one another by HPLC on a
chiral phase or by crystallization with chiral acids, for example
(+)-tartaric acid, (-)-tartaric acid or (+)-10-camphorsulfonic
acid.
[0053] The present invention also relates to the use of at least
one substituted imidazo[1,2-a]-pyridine compound of formula I as an
inhibitor of nitric oxide synthase and/or in pharmaceutical
formulations for treatment of migraine, septic shock,
neurodegenerative diseases, preferably multiple sclerosis,
Parkinson's disease, Alzheimer's disease or Huntington's disease,
inflammatory pain, cerebral ischaemia, diabetes, meningitis,
arteriosclerosis or for wound treatment.
[0054] The present invention also relates to the use of at least
one substituted imidazo[1,2-a]-pyridine compound of formula I, with
the proviso that the radicals R.sup.3 and R.sup.4 do not both
represent a 4-methoxy-phenyl radical if the radicals R.sup.1 and
R.sup.2, which are identical or different, represent a
C.sub.1-4-alkyl radical, a C.sub.1-4-alkoxy radical, an OH radical
or an NO.sub.2 radical, as an inhibitor of nitric oxide synthase
and/or in pharmaceutical formulations for treatment of
inflammations.
[0055] The present invention also relates to the use of at least
one substituted imidazo[1,2-a]-pyridine compound of formula I for
the preparation of a pharmaceutical formulation for treatment of
migraine, septic shock, neurodegenerative diseases, preferably
multiple sclerosis, Parkinson's disease, Alzheimer's disease or
Huntington's disease, inflammatory pain, cerebral ischaemia,
diabetes, meningitis, arteriosclerosis or for wound treatment.
[0056] The present invention also relates to the use of at least
one substituted imidazo[1,2-a]-pyridine compound of formula I, with
the proviso that the radicals R.sup.3 and R.sup.4 do not both
represent a 4-methoxy-phenyl radical if the radicals R.sup.1 and
R.sup.2, which are identical or different, represent a
C.sub.1-4-alkyl radical, a C.sub.1-4-alkoxy radical, an OH radical
or an NO.sub.2 radical, for the preparation of a pharmaceutical
formulation for treatment of inflammations.
[0057] The pharmaceutical formulations used in the invention can
exist as liquid, semi-solid or solid pharmaceutical formulation
forms, for example in the form of injection solutions, drops,
juices, syrups, sprays, suspensions, granules, tablets, patches,
capsules, plasters, suppositories, ointments, creams, lotions,
gels, emulsions, aerosols or in multiparticulate form, for example
in the form of pellets or granules, and can also be administered as
such.
[0058] In addition to at least one substituted
imidazo[1,2-a]-pyridine compound of formula I, the pharmaceutical
formulations according to the invention typically comprise further
conventional physiologically acceptable pharmaceutical auxiliary
substances known to persons skilled in the art, which are
preferably selected from the group consisting of carriers, fillers,
solvents, diluents, surface-active agents, dyestuffs,
preservatives, disintegrating agents, lubricants, greasing agents,
flavorings and binders.
[0059] The choice of the physiologically acceptable auxiliary
substances and the amounts thereof to be employed depend on whether
the pharmaceutical formulation is to be administered orally,
subcutaneously, parenterally, intravenously, intraperitoneally,
intradermally, intramuscularly, intranasally, buccally, rectally or
locally, for example on infections on the skin, the mucous
membranes and on the eyes. Formulations in the form of tablets,
coated tablets, capsules, granules, pellets, drops, juices and
syrups are preferable for oral administration, and solutions,
suspensions, easily reconstitutable dry formulations and sprays are
suitable for parenteral, topical and inhalatory administration.
Compounds of formula I in a depot in dissolved form or in a
plaster, optionally with the addition of agents which promote
penetration through the skin, are suitable formulations for
percutaneous administration. Formulation forms which can be used
orally or percutaneously can also release the compounds of formula
I in a delayed manner.
[0060] The pharmaceutical formulations are prepared with the aid of
conventional means, devices, methods and processes known to persons
skilled in the art, such as are described, for example, in
"Remington's Pharmaceutical Sciences", ed. A. R. Gennaro, 17th ed.,
Mack Publishing Company, Easton, Pa. (1985), in particular in part
8, chapter 76 to 93. The corresponding literature description is
incorporated herein by reference and thus forms part of the
disclosure.
[0061] The amount of the particular compound of formula I to be
administered to the patient can vary and depends, for example, on
the weight or the age of the patient and on the mode of
administration, on the indication and on the severity of the
disease. 0.1 to 5,000 mg/kg, preferably 1 to 500 mg/kg,
particularly preferably 2 to 250 mg of at least one compound of
formula I are conventionally administered per kg of body weight of
the patient.
[0062] Molecular Pharmacology Studies
[0063] The assays used to determine the inhibition of nitric oxide
synthase by the compounds of formula I employed according to the
invention are described in the following text:
[0064] Nitric Oxide Synthase Assay
[0065] This assay allows the determination of the percentage
inhibition of NO synthase by a compound of formula I employed
according to the invention by measuring the NO synthase activity
under the action of the compound. In this procedure, NO synthase is
mixed together with radioactively labelled arginine and the
particular compound of formula I under suitable conditions. After
interruption of the NO formation reaction at a given point in time,
the amount of unreacted arginine is determined directly or
indirectly. Comparison of this amount with the amount of arginine
remaining from the mixture of NO synthase and arginine free of the
test compound of formula I and under otherwise identical conditions
gives the percentage inhibition of NO synthase by the test
compound. This assay can be carried out as follows:
[0066] (a) incubation of NO synthase with labelled arginine as the
substrate in a reaction vessel,
[0067] (b) separation of the labelled arginine from labelled
citrulline formed as the product of the enzymatic reaction at a
point in time at which the concentration of citrulline is
increasing, and
[0068] (c) measurement of the amount of arginine separated in each
case.
[0069] The separation is carried out through a filter plate
membrane.
[0070] This NO synthase assay is particularly suitable for a "high
throughput screening" (HTS) on microtiter plates (MTP).
[0071] HTS NO Synthase Assay: General Procedure
[0072] In this HTS NO synthase assay, radioactive arginine is used
as the substrate. The assay volume can be chosen in the range
between 25 .mu.l and 250 .mu.l, depending on the nature of the
microtiter plate (MTP). Cofactors and coenzymes are added,
depending on the enzyme source used. The incubation of the batches
in this microtiter plate (assay MTP) according to step (a) is
carried out at room temperature for between 5 and 60 minutes,
depending on the enzyme activity (units) used. At the end of the
incubation (step (a)), the plate is placed in a cell harvester
equipped with an MTP which has a cation exchanger membrane as the
filter base (filter MTP). All the batches of the assay MTP are
transferred into this filter MTP and filtered with suction over a
cation exchanger filter plate, i.e., a filter paper loaded with
phosphate groups. The filter MTP is then washed with buffer or
water. Using this procedure, the arginine substrate which remains
is bound to the cation exchanger, while the radioactive citrulline
formed enzymatically is washed out quantitatively. After drying of
the filter MTP and addition of scintillation liquid, the bound
arginine can be counted on a scintillation counter. An NO synthase
reaction which has not been inhibited is reflected in a low
radioactivity. An inhibited enzyme reaction means that the
radioactive arginine has not been reacted. That is to say, a high
radioactivity is found on the filter.
[0073] Materials Used
[0074] Arginine, L-[2,3,4-.sup.3H]-monohydrochloride; order no.
NET-1123, NEN
[0075] CaCl.sub.2 anhydrous; order no. 2388.1000; Merck KGaA
[0076] 1,4-Dithiothreitol (DTT), order no. 708984; ROCHE
[0077] Na.sub.2EDTA dihydrate; order no. 03680; FLUKA
[0078] HEPES, order no. H-3375; SIGMA
[0079] NADPH, tetrasodium salt; order no. 1585363; ROCHE
[0080] TRIS; ORDER No. 93349; FLUKA
1 Enzyme preparation buffer: 50 mM Tris-HCl with 1 mM EDTA: The pH
of the buffer was adjusted to 7.4 at 4.degree. C. Incubation buffer
50 mM HEPES with 1 mM EDTA; 1.25 mM (medium): CaCl.sub.2 and 1 mM
dithiothreitol. The pH of the buffer was adjusted to 7.4 at
25.degree. C. Washing medium: H.sub.2O
[0081] For purposes of clarity, EDTA in the materials list above
means ethylenediamine tetra-acetic acid. HEPES means
4-(2-hydroxyethyl)-1-piper- azineethanesulfonic acid. NADPH means
nicotinamide adenine dinucleotide phosphate. Tris means
tris(hydroxymethyl)aminomethane.
[0082] Enzyme Preparation
[0083] Rat cerebelli were used as the starting tissue. The animals
were narcotized and sacrificed, the brain tissue, the cerebellum,
was removed, 1 ml enzyme preparation buffer (4.degree. C.) was
added per rat cerebellum, and the tissue was broken down with a
Polytron homogenizer for 1 min at 6,000 rpm. Thereafter,
centrifugation was carried out at 4.degree. C. for 15 min at 20,000
g, and the supernatant was then decanted and frozen in portions at
-80.degree. C. (precipitate discarded).
[0084] Incubation Batch:
[0085] 96-well MTP with a "well" capacity of.ltoreq.250 .mu.l were
used Pipetting sequence: see table 1:
2TABLE 1 Substance Molarity i.b. .mu.l *Protein i.b. Incubat.
buffer -- 100 -- Test substance variable; variable; -- preferably
10.sup.-5 M preferably 20 .mu.l NADPH 0.5 mM 20 -- Enzyme --
variable; variable; (see example 3) maximum maximum volume of the
amount of protein enzyme which can be solution = 50 .mu.l employed
= 100 .mu.g [.sup.3H]substrate variable; variable; -- preferably 50
nM preferably 10 .mu.l End volume: max. 250 .mu.l *The protein
determination was carried out by the method of O. H. Lowry et al;
J. Biol. Chem. 193, 265 (1951). The corresponding literature
description is incorporated herein by reference and forms part of
the disclosure. i.b. = in the batch
[0086] When the pipetting operation had ended, a cover was placed
over this MTP (assay MTP). Incubation at 25.degree. C. (room
temperature (RT)) for 5-60 min, depending on the amount and
activity of the enzyme employed.
[0087] The content of the assay MTP was then transferred with the
aid of a 96-well cell harvester into a 96-well cation exchanger MTP
(filter MTP) and filtered with suction. A single washing with 200
ml H.sub.2O (from a trough) followed.
[0088] The plate was then dried for 1 hour at 60.degree. C. in a
drying cabinet. The bottom of the filter MTP was then sealed with a
"back seal" from underneath. Thereafter 35 .mu.l of scintillator
were pipetted in per well. The upper side of the plate was
furthermore sealed with a "top seal". After a waiting time of 1
hour, the plate was measured on a .beta.-counter.
[0089] In HTS operation, the incubation medium, NADPH solution and
enzyme solution were combined before the start of the pipetting
step, so that three separate pipettings did not have to be carried
out in a time-consuming manner.
[0090] Citrulline Assay
[0091] This assay was carried out as described by D. S. Bredt and
S. H. Snyder (Proc. Natl. Acad. Sci. USA (1990), 87, 682-685). The
corresponding literature description is incorporated herein by
reference and forms part of the present disclosure.
[0092] The invention is explained in the following text with the
aid of examples. These explanations are provided merely as examples
and are not intended to, nor should they be understood to, be
limiting.
EXAMPLES
Example 1
2-(4-Methoxy-phenyl)-7-methyl-imidazo[1,2-a]pyridine
[0093] 1.50 g 2-amino-4-methylpyridine were dissolved in 30 ml
analytical grade ethanol; 3.18 g 2-bromo-4'-methoxyacetophenone
were added, and the reaction mixture was heated under reflux for
two hours and subsequently stirred overnight at a temperature of 20
to 25.degree. C. For working up, the reaction mixture was
concentrated to dryness in vacuo, the residue was taken up in
methylene chloride and two-molar aqueous hydrochloric acid, and the
phases were separated. Five per cent sodium hydroxide solution was
added to the very cloudy organic phase until two clear phases were
obtained. The clear phases were separated, the aqueous phase was
extracted again with methylene chloride, and the organic phases
were combined, dried over sodium sulfate and concentrated. The
resulting crude product (2.90 g) was dissolved in 23 ml 2-butanone,
and the hydrochloride was precipitated by addition of 120 .mu.l
water followed by 1.69 ml chlorotrimethylsilane and subsequent
stirring overnight. The yield of
2-(4-methoxy-phenyl)-7-methyl-imidazo[1,2-a]pyridine hydrochloride
was 2.63 g (corresponding to 69% of the theoretical amount).
Example 2
2,7-Dimethyl-imidazo[1,2-a]pyridine
[0094] 1.50 g 2-amino-4-methylpyridine were dissolved in 50 ml
analytical grade ethanol, 2.57 g 1-chloropropan-2-one were added
and the reaction mixture was heated under reflux for two hours and
subsequently stirred overnight at a temperature of 20 to 25.degree.
C. For working up, the reaction mixture was concentrated to dryness
in vacuo, the residue was taken up in methylene chloride and
two-molar aqueous hydrochloric acid, and the phases were separated.
The aqueous phase was rendered basic with five per cent sodium
hydroxide solution and extracted twice with ether, and the ether
extracts were combined, dried over sodium sulfate and concentrated.
The resulting crude product (1.44 g) was dissolved in 12 ml
2-butanone, and the hydrochloride was precipitated by addition of
97 .mu.l water followed by 1.37 ml chlorotrimethylsilane and
subsequent stirring overnight. The yield of
2,7-dimethyl-imidazo[1,2-a]pyridine hydrochloride was 1.68 g
(corresponding to 66% of the theoretical amount).
Example 3
7-Methyl-imidazo[1,2-a]pyridine
[0095] 1.50 g 2-amino-4-methylpyridine were dissolved in 50 ml
methylene chloride; 4.84 g of a 45% by weight aqueous
chloroacetaldehyde solution were added, and the reaction mixture
was heated under reflux overnight using a water separator. For
working up, 2N hydrochloric acid and methylene chloride were added
to the reaction mixture; the phases were separated; the aqueous
phase was rendered basic with five per cent sodium hydroxide
solution and extracted twice with ether, and the ether extracts
were combined, dried over sodium sulfate and concentrated. The
crude product (1.42 g) obtained was dissolved in 12 ml 2-butanone
and the hydrochloride was precipitated by addition of 106 .mu.l
water followed by 1.50 ml chlorotrimethylsilane and subsequent
stirring overnight. The yield of 7-methyl-imidazo[1,2-a]pyridine
hydrochloride was 1.59 g (corresponding to 67% of the theoretical
amount).
Example 4
2-tert-Butyl-7-methyl-imidazo[1,2-a]pyridine
[0096] 1.50 g 2-amino-4-methylpyridine were dissolved in 30 ml
analytical grade ethanol; 2.48 g 1-bromo-3,3-dimethyl-butan-2-one
were added, and the reaction mixture was heated under reflux for
two hours and subsequently stirred overnight at a temperature of 20
to 25.degree. C. For working up, the reaction mixture was
concentrated to dryness in vacuo; the residue was taken up in
methylene chloride and two-molar aqueous hydrochloric acid, and the
phases were separated. The aqueous phase was rendered basic with
five per cent sodium hydroxide solution and extracted twice with
ether, and the ether extracts were combined, dried over sodium
sulfate and concentrated. The resulting crude product (1.84 g) was
dissolved in 14 ml 2-butanone, and the hydrochloride was
precipitated by addition of 89 .mu.l water followed by 1.26 ml
chlorotrimethylsilane and subsequent stirring overnight. The yield
of 2-tert-butyl-7-methyl-imidazo[1,2-a]pyridine hydrochloride was
2.12 g (corresponding to 69% of the theoretical amount).
[0097] Molecular Pharmacology Study
[0098] The compounds prepared according to examples 1 to 4 were
tested in the HTS NO synthase assay as described above. The
inhibition of nitric oxide synthase (10 .mu.M) by the compounds
according to the examples is shown in the following Table 2:
3 TABLE 2 Inhibition of nitric oxide synthase (10 .mu.M) Example
no.: in per cent 1 39 2 68 3 53 4 89
[0099] The foregoing description and examples have been set forth
merely to illustrate invention and are not intended to be limiting.
Since modifications of the described embodiments incorporating the
spirit and substance of the invention may occur to persons skilled
in the art, the invention should be construed broadly to include
all variations within the scope of the appended claims and
equivalents thereof.
* * * * *